A semiconductor integrated circuit such as a system LSI includes, as its configuration elements, bus masters, bus slaves and buses connecting the bus masters and the bus slaves to each other. In this type of semiconductor integrated circuit, clock gating is widely used as a technique for reducing power consumption.
Clock gating is a technique which reduces power consumption by shutting off clocks supplied, for example, to bus slaves. Clock gating is featured in that the state transition time between a normal state and a low power-consumption state is comparatively short and the clock tree power, which constitutes the majority of a dynamic current, can be suppressed.